JP4160393B2 - First stage clutch - Google Patents

Abstract

A multi-speed transmission assembly for a rotary power tool. The transmission assembly includes a plurality of transmission stages, with at least two of the transmission stages employing a movable reduction element that permits the transmission stage to be operated in an active mode and an inactive mode. The movable reduction elements are coupled to a switching mechanism that switches the reduction elements in a predetermined manner to provide at least three-gear reduction or speed ratios.

Description

  This application claims the benefit of US Provisional Application No. 60 / 263,379, filed Jan. 23, 2001. Another feature of the present invention is that US application Ser. No. 09 / 964,226 entitled “Multi-Speed Power Tool Power Transmission Device,” a co-pending application assigned to the same assignee, “360 degree clutch Discussed and claimed in U.S. Application No. 09 / 965,108 entitled "Color" and U.S. Application No. 09 / 963,905 entitled "Housing with Functional Overmolded Member". .

  The present invention generally relates to power tools such as rotary drills and electric screwdrivers. In particular, the present invention relates to a clutch mechanism that is operated based on a magnitude of torque output from a first stage of a multi-speed power transmission device.

  Today, power tool manufacturers have introduced rotary power tools with variable speed motors, allowing users of these tools to fully control the output speed of the tools, thereby enabling a variety of operations without relying on additional dedicated tools. Is trying to be able to. Many commercially available tools include a three-stage, two-speed power transmission that allows for greater control over the speed of these tools.

  Known power transmission mechanisms typically include a wide range of output speeds that allow a variety of tool operations, such as drilling with a large diameter hole saw, installing drywall or large lag screws, and performing high speed drilling operations. There was no power transmission mechanism that could generate torque. Single or double speed power transmissions commonly used with such tools typically do not have sufficient deceleration capability to allow for various uses of such power transmissions, making them useful for high torque operation. When set to, high-speed performance tended to decrease. In addition, rechargeable batteries used in many early cordless rotating power tools are used at low speeds and high torque operation due to the amount of energy consumed and the rate at which the power tool consumes energy during operation. It was not very suitable for. As a result, consumers have two different rotary power tools, medium load tools for “standard” applications such as drilling and tightening, and high load tools with low speed and high torque output for more demanding operations. In many cases, they were forced to purchase.

  With the advent of the latest high capacity, high voltage batteries, it is now possible to meet the energy demands of power tools used at low speeds and high torque operation. However, there remains a need in the art for a clutch mechanism that can be used through a relatively wide range of deceleration capabilities.

  A typical clutch mechanism allows a tool user to limit the torque output at the final stage of the tool power transmission. Typically, these clutch mechanisms use a spring that biases the two parts of the clutch into engagement. When the torque output by the power transmission device exceeds a predetermined clutch setting, the biasing force exerted by the spring is not sufficient to maintain the part of the clutch in the engaged state, and one part of the clutch The other part of the clutch can be rotated. The relative movement of these two parts effectively prevents the transmission of torque to the tool output shaft.

  The use of such a clutch mechanism with a power transmission device having a relatively wide deceleration range is biased by a spring so that the clutch part is allowed to be properly engaged and disengaged over the entire deceleration range. It is often impractical for the simple reason that the force does not have a sufficient range. Therefore, it is relatively common to supply several differently sized springs to the clutch mechanism, and it is necessary for the user to select and install the appropriate sized spring for the given task. Become. While this method is effective, it is nevertheless time consuming and inconvenient.

  In one preferred form, the present invention provides a clutch mechanism for use in a power tool having a multi-speed power transmission assembly. The clutch mechanism has a clutch member and a follower member. The clutch member is coupled to a member of the power transmission assembly that is proximate to the torsional input of the power transmission assembly and must be in a non-rotating position for the power transmission assembly to perform torque multiplication operations. The follower members are biased to engage the clutch members and prevent relative rotation between them. When the clutch member and the power transmission device assembly are coupled to each other, the power transmission device assembly can perform a torque multiplication operation. However, when the torsion acting on the clutch member is sufficient to overcome the frictional engagement between the follower and the clutch member, the clutch member and the power transmission assembly rotate and perform torque multiplication operation. Block the ability of the power transmission to continue.

  Additional advantages and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.

  Referring to FIGS. 1 and 2 of the drawings, a power tool constructed in accordance with the teachings of the present invention is indicated generally by the reference numeral 10. As those skilled in the art will appreciate, preferred embodiments of the present invention may be either corded or cordless (battery powered) devices such as portable screwdrivers or drills. In the particular embodiment illustrated, the power tool 10 includes a housing 12, a motor assembly 14, a multi-speed power transmission assembly 16, a clutch mechanism 18, an output spindle assembly 20, a chuck 22, a trigger A cordless drill having an assembly 24 and a battery pack 26. As those skilled in the art will appreciate, some components of the power tool 10 such as the chuck 22, trigger assembly 24, and battery pack 26 are conventional in nature and need to be described in particular detail in this application. Absent. To more fully understand the operation of the conventional functions of the power tool 10, various publications may be referred to. One example of such a publication is US Patent Application Publication No. 5,897,454, issued April 27, 1999, assigned to the same assignee, the entire disclosure of which is incorporated by reference.

  The housing 12 includes an end cap assembly 30 and a handle shell assembly 32 that includes a pair of mating handle shells 34. The handle shell assembly 32 includes a handle portion 36 and a drive train or body portion 38. The trigger assembly 24 and the battery pack 26 are mechanically coupled to the handle portion 36 and electrically coupled to the motor assembly 14. The body portion 38 includes a motor cavity 40 and a power transmission device cavity 42. The motor assembly 14 is housed in a motor cavity 40 and includes a rotary output shaft 44 that extends into a power transmission device cavity 42. A motor pinion 46 having a plurality of gear teeth 48 is coupled for rotation with the output shaft 44. The trigger assembly 24 and the battery pack 26 cooperate to selectively provide power to the motor assembly 14 in a generally well known manner that controls the speed and direction in which the output shaft 44 rotates. .

  The power transmission device assembly 16 is housed in the power transmission device cavity 42 and includes a speed selection mechanism 60. A motor pinion 46 couples the power transmission assembly 16 to the output shaft 44 and transmits a relatively high speed, low torque drive input to the power transmission assembly 16. The power transmission assembly 16 includes a plurality of deceleration elements that selectively engage the speed selection mechanism 60 to provide a plurality of speed ratios. Each speed ratio multiplies the speed and torque of the drive input by a predetermined method, and outputs the output speed and torque of the power transmission assembly 16 to a relatively low speed, high torque output and a relatively high speed, low torque output. Can be varied as desired between. The power transmission device output is supplied to the output spindle assembly 20, and the chuck 22 is coupled to the output spindle assembly 20 so that the torque is transmitted to a tool bit (not shown). Clutch mechanism 18 is coupled to power transmission assembly 16 and operates to limit the magnitude of torque associated with the drive input to a predetermined selectable torque limit.

Functional overmold
With particular reference to FIGS. 2-9, an end cap assembly 30 is illustrated and includes an end cap shell 100 and an overmold member 102. In the example provided, the end cap shell 100 is injection molded from a plastic material such as ABS. The end cap shell 100 forms an end cap cavity 104 sized to receive a portion of the motor assembly 14 that extends behind the handle shell assembly 32. A plurality of first and second radial tab openings 108 and 110 and an abutment surface 128 are formed on the front surface 114 of the end cap outer shell 100 and a plurality of screw bosses 116 are formed on the outer periphery of the end cap shell 100. The The first and second radial tab openings 108 and 110 are each sized to receive a first radial tab 120 and a second radial tab 122 formed in the rear face 124 of the handle shell 34. The first and second radial tab openings 108 and 110 cooperate with the first and second radial tabs 122 to properly align the end cap shell 100 with the handle shell assembly 32 and to each other. Prevent relative rotation. The arcuate portion 128 of the front surface 114 of the end cap shell 100 is at an angle that matches the abutment surface 132 of the rear surface 124 of the handle shell 34. Due to the screw boss 116, the end cap outer shell 100 can be fixedly coupled to the motor cover 136 by a plurality of screws 138. The geometric shape of the motor cover 136 is such that it fits within the handle shell 34. That is, when the end cap outer shell 100 is fixed to the motor cover 136, the end cap outer shell 100 is fixedly held with respect to the rear surface 124 of the handle outer shell assembly 32, and the rear handle opening of the handle outer shell assembly 32 is held. 139 is closed.

  A plurality of side openings 140 are formed in the sides of the end cap shell 100 so that air flows through the handle shell assembly 32 and causes the motor assembly 14 to be routed in a manner well known in the art. Allow cooling. A plurality of rear openings 144 are formed in the rear of the end cap shell 100, each rear opening 144 having a recessed portion 146 that extends only partially to the outer surface 148 of the end cap shell 100 and an end cap shell. A through portion 150 that extends completely through 100 is included. A pair of retention tabs 152 are formed and extend from the inner surface 154 of the end cap shell 100 into the end cap cavity 104. A channel 156 is formed in the inner surface 154 of the end cap outer shell 100 and intersects each of the rear opening 144 and the retention tab 152.

  The overmold member 102 is formed from an elastic material such as a thermoplastic elastomer (eg, HYTREL® manufactured by EI du Pont de Nemours and Company) and is injection molded. In the process, the end cap shell 100 is formed and bonded to it. In the particular example provided, the overmold member 102 includes a plurality of bumper members 170, a pair of vibration isolation devices 172, and a connecting member 174. Each bumper member 170 is from about 0.5 mm to about 1.5 mm, preferably about 0.5 mm, from a point substantially coincident with the inner surface 154 of the end cap outer shell 100 to a point behind the outer surface 148 of the end cap outer shell 100. It extends by 0.75mm. With such a structure, the damper member 170 provides some degree of shock absorption and can reduce the possibility of damaging the end cap outer shell 100 if the tool 10 falls. Further, the operator may need to apply a relatively large force to the tool 10 as in the case of drilling a large-diameter hole using a hole saw. In such a situation, the operator tilts the body and pushes the rear part of the tool 10 to apply a force that coincides with the axis of the chuck 22. In these situations, the bumper member 170 provides the worker with a relatively soft and comfortable surface that is non-slip and helps damp vibrations transmitted to the operator.

  A vibration isolator 172 is formed around the retention tab 152 on the inner surface 154 of the end cap outer shell 100. In the example provided, each vibration isolator 172 includes an annular member 180 that extends forward of the inner surface 154 of the end cap outer shell 100. With such a structure, the end cap outer shell 100 can engage the vibration isolator 172 with the outer diameter 14a, and the rear surface 14b of the motor housing 14c can hold the motor 14d fixedly in the motor cover 136. This prevents components of the motor assembly 14 from moving along the longitudinal axis of the tool 10 and damps vibrations that occur during operation of the motor assembly 14. The connecting member 174 fixes and connects each bumper member 170 and the vibration isolator 172. The connecting member 174 provides a flow path through which the elastic material flows when forming the bumper member 170 and the vibration isolator 172. Further, the connecting member 174 interconnects the bumper member 170 and the vibration isolator 172 so that it is difficult to remove from the end cap outer shell 100.

  As those skilled in the art will appreciate, this aspect of the invention provides a seal between two or more components, damps vibrations, and positions one component relative to another. , May be incorporated into various other locations within the handle assembly 32. One such example is illustrated in FIGS. 10 and 11, where the vibration isolator 172 is modified to extend along the outer periphery of a portion of the end cap cavity 104, and the rear surface 14b of the motor 14d. Contact to seal. The vibration isolator 172 seals the interface between the end cap shell 100 and the motor assembly 14, and the bumper member 170 seals the rear opening 144 in the end cap shell 100. The space 188 formed by the vibration isolator 172 is filled with grease or another suitable lubricant that lubricates the motor armature bearing 190.

Power Transmission Device Assembly Referring to FIG. 12, a power transmission device assembly 16 that is a three-stage, three-speed power transmission device including a power transmission device sleeve 200, a reduction gear set assembly 202, and a speed selection mechanism 60 is provided. Indicated. Still referring to FIGS. 13-17, the power transmission sleeve 200 includes a wall member 210 that generally forms a power transmission bore or hollow cavity 212 within which a reduction gear set assembly 202 is disposed. It is. The power transmission device sleeve 200 includes a main body 214 and a base 216. The diameter of the body 214 of the power transmission device sleeve 200 is substantially uniform and is generally smaller than the base 216. The inner diameter of the base 216 is sized to receive the cylindrical top portion 220 of the motor cover 136.

  A plurality of protruding lands 226 are formed on the base 216. The protruding lands 226 form a plurality of first grooves 228 on the outer surface 230 of the base 216 and a plurality of second grooves 232 on the inner surface of the base 216. The first groove 228 is configured to receive an alignment rib 238 that is formed in the inner surface 242 of the handle shell 34 to position the power transmission device sleeve 200 in the handle shell 34. Together to prevent relative rotation between the power transmission sleeve 200 and the housing 12. Preferably, the first groove 228 and the alignment rib 238 allow the power transmission sleeve 200 to be combined with the handle shell 34 in only one direction (ie, the first groove 228 and the alignment rib 238). The configuration prevents the power transmission device sleeve 200 from rotating 180 degrees from a fixed position with respect to the handle outer shell 34). The second groove 232 is discussed in further detail below.

  The body 214 of the power transmission sleeve 200 is shown to include a cylindrical body portion 246 and a pin housing portion 248. In the particular embodiment illustrated, the cylindrical body portion 246 includes a selector cam guide 250, a plurality of lubricant grooves 252, and first and second sets of ring engagement teeth 254 and 256. It is. The selector cam guide 250 has a generally rectangular cross section and extends outwardly from the top of the outer surface 258 of the body portion 246. The lubricant groove 252 is formed concentrically along the upper half of the outer periphery of the main body portion 246. The lubricant groove 252 has a depth of about 0.0254 mm (about 0.01 inch) to about 0.0762 inch (about 0.030 inch) for holding a lubricant such as grease in the upper half of the outer periphery of the body portion 246. Have. The operation of the selector cam guide 250 and the lubricant groove 252 is described in detail below.

  Protruding bead 264 separates the interior of body portion 246 into first and second portions 260 and 262. A first set of ring engaging teeth 254 is formed on the inner surface 266 of the body portion 246 and extends rearwardly from the protruding bead 264 toward the base 216. A second set of ring engaging teeth 256 is also formed on the inner surface of the body portion 246, which extends forward from the protruding bead 264. The teeth 268 of the first and second sets of ring engaging teeth 254 and 256 are evenly spaced along the inner surface 266 of the body portion 246. The shape of each tooth 268 of the first and second sets of ring engaging teeth 254 and 256 is such that each tooth extends from the protruding bead 264 and has a pair of parallel engaging surfaces 270 and ends with a tip portion 272. It is the same in that. As described in detail below, the tip portion 272 of each tooth 268 is rounded and tapered to improve the ability to engage and engage a portion of the reduction gear set assembly 202.

  Pin housing portion 248 extends downwardly from body portion 246 over a substantial portion of the length of body portion 246. Actuator opening 274 is formed in pin housing portion 248 and extends rearwardly through base 216 of power transmission sleeve 200. In the particular embodiment illustrated, the actuator opening 274 is stepped and has a first portion 276 having a first diameter at the rear of the power transmission sleeve 200 and a smaller front portion of the power transmission sleeve 200. A second portion 278 having a second diameter. In the illustrated example, the first portion 276 of the actuator opening 274 breaks through the wall of the first housing portion 260 to form a groove 280 in the inner surface 234 of the base 216. Pin housing portion 248 is discussed in further detail below.

  A first pair of clip slots 284 and a second pair of clip slots 286 are formed in the power transmission sleeve 200 along the side of the power transmission sleeve 200 parallel to the longitudinal axis of the power transmission sleeve 200. Extend. A first pair of clip slots 284 are formed through the sides of the body portion 246 behind the protruding beads 264 and extend rearward toward the base 216. The depth of the first pair of clip slots 284 is such that the first pair of clip slots 284 does not extend through a portion of the wall member 210 that forms the base 216. A second pair of clip slots 286 are also formed through the sides of the body portion 246 and extend from the front of the protruding bead 264 and through the front surface 288 of the power transmission sleeve 200.

  Referring to FIGS. 12, 13, 18 and 23, the reduction gear set assembly 202 includes a first reduction gear set 302, a second reduction gear set 304, and a third reduction gear set 306. included. The first, second and third reduction gear sets 302, 304 and 306 operate in an operating mode and a non-operating mode. In operation in the operating mode, the reduction gear set performs speed reduction and torque multiplication operations, and in operation in the non-operation mode of the reduction gear set, the speed reduction gear set includes the rotational input speed and torque provided to the reduction gear set. Provides output with approximately equal speed and torque. In the particular embodiment illustrated, the first, second, and third reduction gear sets 302, 304, and 306 are each planetary gear sets. However, as those skilled in the art will recognize, various other types of reduction gear sets that are well known in the art may be substituted for the one or more reduction gear sets that form the reduction gear set assembly 202. You may substitute.

  As shown, the first reduction gear set 302 includes a first reduction element or ring gear 310, a first set of planetary gears 312, and a first reduction carrier 314. The first ring gear 310 has an annular structure and has a plurality of gear teeth 310a formed along an inner diameter. The clutch surface 316 is formed on the outer periphery of the front surface 318 of the first ring gear 310, which is discussed in further detail below. The first ring gear 310 is disposed in a portion of the hollow cavity 212 formed by the base 216. The front surface 318 of the first ring gear 310 is in contact with a step 320 formed in the power transmission device sleeve 200 so that the first ring gear 310 cannot move forward in the hollow cavity 212. Restricted.

  The first deceleration carrier 314 is formed in the shape of a flat cylinder and has a plurality of pins 322 extending from its rear face 324. A plurality of gear teeth 314a are formed on substantially the entire outer periphery of the first reduction carrier 314, and valleys 314b are formed between each pair of adjacent gear teeth 314a. Due to the spacing of the gear teeth 314a, one of the troughs (ie, trough 314b ') is relatively larger than the remaining trough 314b due to the omission of the outer peripheral teeth 314a of the first reduction carrier 314. In the particular embodiment illustrated, the gear teeth 314 a of the first reduction carrier 314 are shaped so as not to mesh with and engage the gear teeth 310 a of the first ring gear 310.

  With particular reference to FIGS. 19 and 20, the outline of the gear teeth 314a is shown in more detail. As shown, each gear tooth 314a has a gentle rounding 326 at the front face 328 of the first reduction carrier 314, but a sharp end at the rear face 324 of the first reduction carrier 314. Roundness 330 is also formed in the valley 314b between the gear teeth 314a.

  Returning to FIGS. 12, 13, 15, 18, and 23, a first thrust washer 332 having a first annular portion 334, a second annular portion 336, and a plurality of retaining tabs 338 is provided. 1 reduction gear set 302 is disposed behind. Since the retention tab 338 engages with the second groove 232 of the base 216 of the power transmission device sleeve 200, relative rotation between the first thrust washer 332 and the power transmission device sleeve 200 is prevented. Since the inner diameter of the base 216 is sized to receive the motor cover 136, the front surface 340 of the motor cover 136 prevents axial movement of the first thrust washer 332. The first annular portion 334 contacts the rear surface 342 of the first ring gear 310 to provide a wear surface and controls the amount that the first ring gear 310 can move axially. The second annular portion 336 is axially spaced from the first annular portion 334 and extends forward of the first annular portion 334 and provides a wear surface for the first set of planetary gears 312. Again, they control the amount that they can move axially.

The first set of planetary gears 312 includes a plurality of planetary gears 344, each of which has a generally cylindrical shape and is formed at the center with a plurality of gear teeth 344a formed on the outer periphery. Pin opening 346. Each planetary gear 344 is rotatably supported on one associated pin 322 and the first reduction carrier 314 and is arranged so that its teeth 344a are in meshing engagement with the teeth 310a of the first ring gear 310. The Since the protruding portion 348 is formed on the front and rear surfaces 350 and 352 of each planetary gear 344, the teeth 344a rub against the first reduction carrier 314 and the first thrust washer 332 to provide a power transmission assembly. The generation of dust or debris that can impair the performance of 16 and shorten the operating life is prevented. Further, since the teeth 46 a of the motor pinion 46 on the output shaft 44 are engaged with and engaged with the teeth 344 a of the planetary gear 344, the motor pinion 46 serves as a sun gear for the first reduction gear set 302.

  The second reduction gear set 304 is disposed in a portion of the hollow cavity 212 formed by the first housing portion 260 and includes a second sun gear 358, a second reduction element or ring gear 360, Two sets of planetary gears 362 and a second reduction carrier 364 are included. The second sun gear 358 is fixed to rotate with the first reduction carrier 314. The second sun gear 358 includes a plurality of gear teeth 358 a extending forward of the front face 328 of the first reduction carrier 314.

  The second ring gear 360 has an annular structure and has a plurality of gear teeth 360a formed along the inner diameter. The gear teeth 360a may be greatly chamfered at the rear surface 366 of the second ring gear 360, but may be abruptly terminated at the front surface 368. More preferably, a large rounding 369 is formed on the rear face 366 and the side of each gear tooth 360a, wherein the large rounding 369 on the gear tooth 360a is connected to the second ring gear 360 and the first ring gear 360a. Larger rounds 369 are utilized rather than large chamfers to provide better engagement with the deceleration carrier 314.

  A plurality of sleeve engaging teeth 370 are formed on the outer periphery of the second ring gear 360. The sleeve engaging teeth 370 extend forward toward the front surface 368 of the second ring gear 360 and end at a tip portion 372 that is rounded forward and inward and tapered. An annular clip groove 374 is formed on the outer periphery of the second ring gear 360. In the illustrated example, the clip groove 374 is a rectangular slot having a pair of side walls 376. Clip groove 374 is discussed in further detail below.

  The second deceleration carrier 364 is formed in a flat cylindrical shape and has a plurality of pins 378 extending from its rear surface 380. It is shown that the second set of planetary gears 362 includes a plurality of planetary gears 382. Each planetary gear 382 has a generally cylindrical shape, and has a plurality of gear teeth 382 a formed on the outer periphery and a pin opening 384 formed in the center. Each planetary gear 382 is rotatably supported on an associated pin 378 and a second reduction carrier 364, with the gear teeth 382a of the planetary gear 382 meshing with the gear teeth 360a of the second ring gear 360. Arranged to engage. Further, the gear teeth 358 a of the second sun gear 358 mesh with and engage with the gear teeth 382 a of the planetary gear 382.

  The third reduction gear set 306 is disposed in a portion of the hollow cavity 212 formed by the second housing portion 262, and includes a third sun gear 398, a third reduction element or ring gear 400, A third set of planetary gears 402 and a third reduction carrier 404 are included. The third sun gear 398 is fixed for rotation with the second reduction carrier 364. The third sun gear 398 includes a plurality of gear teeth 398 a that extend forward of the front surface 406 of the second reduction carrier 364.

  The third ring gear 400 has an annular structure and has a plurality of gear teeth 400a formed along the inner diameter. The gear teeth 400a may be greatly chamfered on the front surface 412 of the third ring gear 400, but may end sharply on the rear surface 414. More preferably, a large rounding 407 is formed on the front surface 412 and the side surface of each gear tooth 400a, wherein the large rounding 407 on the gear tooth 400a corresponds to the third ring gear 400 and the third ring gear 400a. Large rounds 407 are utilized rather than large chamfers to provide better engagement with the other deceleration carrier 404. A plurality of sleeve engaging teeth 418 are formed on the outer periphery of the third ring gear 400. The sleeve engaging teeth 418 extend rearward toward the rear surface 414 of the third ring gear 400 and end at a tip portion 420 that is rounded back and inward and tapered. An annular clip groove 422 is formed on the outer periphery of the third ring gear 400. In the illustrated example, the clip groove 422 is a rectangular slot having a pair of side walls 424. Clip groove 422 is discussed in further detail below.

  The third deceleration carrier 404 is formed in the shape of a flat cylinder and has a plurality of pins 428 extending from its rear face 430. A plurality of gear teeth 404a are formed on substantially the entire outer periphery of the third reduction carrier 404, and valleys 404b are formed between each pair of adjacent gear teeth 404a. Due to the spacing of the teeth 404a, one of the valleys (i.e., the valley 404b ') is relatively larger than the remaining valleys 404b due to the omission of the outer teeth 404a of the third deceleration carrier 404. In the particular embodiment illustrated, the gear teeth 404a of the third reduction carrier 404 are shaped such that they do not mesh and engage the gear teeth 382a of the second planetary gear 382.

  Further briefly referring to FIGS. 21 and 22, the outline of the gear teeth 404a is illustrated in more detail. As shown, the rear surface 430 of the third deceleration carrier 404 is chamfered and large rounds 434 are formed on each side of the teeth 404a and valleys 404b. Each gear tooth 404 a abruptly terminates at the front face 436 of the third reduction carrier 404.

  Returning to FIGS. 12, 13, 15, 18, and 23, a third set of planetary gears 402 is shown including a plurality of planetary gears 438. Each planetary gear 438 is generally cylindrical in shape and has a plurality of gear teeth 438a formed on the outer periphery and a pin opening 440 formed through the center. Each planetary gear 438 is rotationally supported on an associated pin 428 and a third reduction carrier 404, with the gear teeth 438a of the planetary gear 438 meshing with the gear teeth 400a of the third ring gear 400. Arranged to engage. Since the protruding portion 442 is formed on each of the front and rear surfaces of the planetary gear 438, the gear teeth 438a rub against the third reduction carrier 404 to impair the performance of the power transmission assembly 12 and shorten the operating life. Generation of possible dust or debris is prevented. A second thrust washer 450 is disposed around the third sun gear 398 and the teeth 398a of the third sun gear 398 are in meshing engagement with the gear teeth 438a of the planetary gear 438. The second thrust washer 450 includes a plurality of retaining tabs 452 that engage with corresponding tab grooves 454 (FIG. 13) formed in the inner surface 266 of the body portion 246 of the power transmission sleeve 200. Configured to do. The holding tab 452 and the tab groove 454 cooperate to prevent relative rotation between the second thrust washer 450 and the power transmission sleeve 200.

  The output spindle assembly 20 includes power transmission means 458 that couples the spindle 460 to rotate with the third reduction carrier 404 to transmit drive torque from the reduction gear set assembly 202 to the chuck 22. To do. This power transmission means 458 is well known in the art and can be easily adapted to the power transmission assembly of the present invention. Therefore, a detailed discussion of the power transmission means 458 is not included in this application.

  13, 13 a, 13 b, 16, 17, 18, and 23 to 28, the speed selection mechanism 60 includes a first position 500, a second position 502, and a third position. A switch portion 510 is movable between the position 504 and receives a speed change input, and an actuator portion 512 that operates the reduction gear set assembly 202 in response to the speed change input. Actuator portion 512 is operatively coupled to reduction gear set assembly 202 and is operative in response to movement of switch portion 510 between first, second, and third positions 500, 502, and 504. The second and third reduction gear sets 304 and 306 are moved between inactive modes. In the particular embodiment illustrated, the actuator portion 512 includes a rotation selector cam 520, a plurality of wire clips 522, and a spring member 523. Each wire clip 522 is formed from a round wire bent into a semi-circle 524 and has a pair of tabs 526 that extend outwardly from the semi-circle 524 and are located approximately on the center line of the semi-circle 524. The semicircle 524 is sized to fit in the clip grooves 374 and 422 of the second and third ring gears 360 and 400, respectively. In this regard, the semicircle 524 does not extend radially outward of the associated ring gear (360, 400) and does not catch the side walls (376, 424) of the clip grooves (374, 422). In the example provided, the side walls (376, 424) of the clip grooves (374, 422) have a spacing of about 0.05 inch, and the diameter of the wire forming the wire clip 522 is about 0.00. 1016 mm (0.04 inch).

  The tab 526 of the wire clip 522 extends outside the hollow cavity 212 and enters an associated one of the clip slots (284, 286) formed in the power transmission sleeve 200. The tab 526 is long enough to extend outside the outer surface 258 of the body 214 of the power transmission sleeve 200, but outside the portion of the first clip slot 284 of the base 216 of the power transmission sleeve 200. It does not extend in the radial direction. Such a shape of the wire clip 522 allows the wire clip 522 to be installed on the second and third ring gears 360 and 400, after which these assemblies are hollowed along the longitudinal axis of the power transmission sleeve 200. Since it can be inserted into the cavity 212, the assembly of the power transmission device assembly 16 is facilitated.

  With particular reference to FIGS. 13 and 27a-27c, a rotary selector cam 520 including an arcuate selector body 530, a switch tab 532, and a plurality of spacing members 534 is illustrated. A pair of first cam slots 540a and 540b, a pair of second cam slots 544a and 544b, a spring opening 546, and a guide opening 548 are formed through the selector body 530. The selector body 530 is dimensioned to slide-fit into the outer diameter of the body portion 246 of the power transmission device sleeve 200. Guide opening 548 is generally rectangular in shape and is sized to engage the front and rear surfaces of selector cam guide 250. The guide opening 548 is significantly larger than the width of the selector cam guide 250 so that the rotation selector cam 520 is on the power transmission sleeve 200 at a first rotational position, a second rotational position, and a third rotational position. It is a dimension which can be rotated between. The selector cam guide 250 cooperates with the guide opening 548 to limit the amount that the rotation selector cam 520 can rotate on the power transmission device sleeve 200, when the rotation selector cam 520 is in the first rotation. When in position, the first lateral side of the selector cam guide 250 contacts the first lateral side of the guide opening 548 and when the rotational selector cam 520 is in the third rotational position. The second lateral side of the selector cam guide 250 comes into contact with the second lateral side of the guide opening 548.

  The first cam slots 540a and 540b are each sized to receive one of the tabs 526 of the wire clip 522 that engages the second ring gear 360. In the particular embodiment illustrated, the first cam slot 540a includes a first section 550, a second section 552, and an intermediate section 554. The first section 550 is at a first predetermined distance from a reference plane 558 that is perpendicular to the longitudinal axis of the rotation selector cam 520, and the second section 552 is second from the reference plane 558. It is at a position separated by a predetermined distance. The middle section 554 couples the first and second sections 550 and 552 to each other. The shape of the first cam slot 540b is the same as the first cam slot 540a, but the first, second and middle sections 550, 552 and 554 in the first cam slot 540b are respectively The difference is that it rotates relative to the rotation selector cam 520 so that it is located 180 ° away from the first, second and middle sections 550, 552 and 554 in the first cam slot 540a. .

Each of the second cam slots 544a and 544b is dimensioned to receive one of the tabs 526 of the corresponding one wire clip 522. In the particular embodiment illustrated, the second cam slot 554a includes a first section 560, a second section 562, a third section 564, and a pair of intermediate sections 566 and 568. It is. The first and third sections 560 and 564 are at a third predetermined distance from the reference plane, and the second section 562 is at a fourth predetermined distance from the reference plane 558. The middle section 566a couples the first and second sections 560 and 562 to each other, and the middle section 568 couples the second and third sections 562 and 564 to each other. The shape of the second cam slot 544b is the same as the second cam slot 544a, but the first, second, third and middle sections 560, 562, 564 in the second cam slot 544b and Rotation selector cams such that 566 and 568 are located 180 degrees away from the first, second, third and middle sections 560, 562, 564 and 566 and 568 in the second cam slot 544a, respectively. The difference is that it rotates with respect to 520.

  Because the tab 526 of the wire clip 522 engages the first cam slots 540a and 540b and the second cam slots 544a and 544b, the rotation selector cam 520 is the first on the power transmission device sleeve 200. The first and second reduction gears 314 and 404 can rotate between the first, second, and third positions 500, 502, and 504, respectively. Selectively engage and disengage. While the rotation selector cam 520 rotates, the first cam slots 540a and 540b and the second cam slots 544a and 544b limit the wire tab 526 of the associated wire clip 522 and the wire tab 526 Move along the longitudinal axis of the power transmission sleeve 200 in the associated one of the first and second clip slots 284 and 286. That is, the rotation selector cam 520 operates to convert the rotational direction input to the axial output, causing the wire clip 522 to move axially in a predetermined manner. Lubricant (not specifically shown) is applied to a lubricant groove 252 formed in the body portion 246 of the power transmission sleeve 200 to lubricate the interface between the power transmission sleeve 200 and the rotation selector cam 520. Used.

  When the rotation selector cam 520 is placed in the first rotational position 500, the tab 526 of the wire clip 522 that engages the second ring gear 360 is in the first section 550 of the first cam slots 540a and 540b. And the tab 526 of the wire clip 522 that engages the third ring gear 400 is disposed in the first section 560 of the second cam slots 544a and 544b. That is, when the rotation selector cam 520 is disposed at the first rotational position, the second and third ring gears 360 and 400 are in meshing engagement with the second and third planetary gears 362 and 402, respectively. As shown in FIG. 23, the second and third ring gears 360 and 400 are simultaneously engaged with the second and third planetary gears 362 and 402. The sleeve engagement teeth 370 and 418 of the 400 are arranged to mesh and engage with the first and second sets of ring engagement teeth 254 and 256, respectively, to transmit power to the second and third ring gears 360 and 400. Relative rotation with the device sleeve 200 is prevented and the power transmission assembly 16 is provided with a first overall gear reduction or speed ratio 570. As those skilled in the art will appreciate, the tip portions 272 of the teeth 268 of the first and second sets of ring engaging teeth 254 and 256 and the tip portions 372 and 420 of the sleeve engaging teeth 370 and 418 are respectively rounded. The taper improves the ability of the power transmission assembly 16 to engage and engage in response to axial position movement along the longitudinal axis.

  When the rotation selector cam 520 is placed in the second rotational position 502, the tab 526 of the wire clip 522 that engages the second ring gear 360 is in the first section 550 of the first cam slots 540a and 540b. And the tab 526 of the wire clip 522 that engages the third ring gear 400 is disposed in the second section 562 of the second cam slots 544a and 544b. That is, when the rotation selector cam 520 is placed in the second rotational position, the second ring gear 360 meshes with and engages with the second planetary gear 362, while the third ring gear 400 is in contact with the third planetary gear 402. And the third deceleration carrier 404 in meshing engagement. When the rotation selector cam 520 is disposed at the second rotational position 502, the sleeve engagement teeth 370 of the second ring gear 360 are in meshing engagement with the first set of ring engagement teeth 254, and The sleeve engagement teeth 418 of the third ring gear 400 do not mesh with and engage with the second set of ring engagement teeth 256. That is, as illustrated in FIG. 24, the relative rotation between the second ring gear 360 and the power transmission device sleeve 200 is prevented, but the third ring gear 400 and the power transmission device sleeve 200 are prevented from rotating. Relative rotation between is allowed, thus providing the power transmission assembly 16 with a second overall gear reduction or speed ratio 572.

When the rotation selector cam 520 is placed in the third rotational position 504, the tab 526 of the wire clip 522 that engages the second ring gear 360 is in the second section 552 of the first cam slots 540a and 540b. And the tab 526 of the wire clip 522 that engages the third ring gear 400 is disposed in the third section 564 of the second cam slots 544a and 544b. That is, when the rotation selector cam 520 is placed in the third rotational position, the second ring gear 360 meshes and engages both the second planetary gear 362 and the first reduction carrier 314, The ring gear 400 meshes and engages only with the third planetary gear 402. When the rotation selector cam 520 is disposed at the third rotational position 504, the sleeve engagement teeth 370 on the second ring gear 360 are disposed so as not to mesh with and engage with the first set of ring engagement teeth 254. The sleeve engagement teeth 418 on the third ring gear 400 are in meshing engagement with the second set of ring engagement teeth 256 so that relative rotation between the second ring gear 360 and the power transmission sleeve 200 is achieved. Is allowed but relative rotation between the third ring gear 400 and the power transmission sleeve 200 is blocked, providing the power transmission assembly 16 with a third overall gear reduction or speed ratio 574.

  In the example shown in FIGS. 13, 27 b and 28, the spring member 523 is formed from a flat rectangular piece of spring steel and includes a flat Z-shaped portion 580 and a protruding portion 584. Since the flat Z-shaped portion 580 is configured to wrap around two reinforcing bars 586 that extend into the spring opening 546, the protruding portion 584 is maintained in place, and the spring force is applied to the rotation selector cam 520, the spring member 523, and the like. Communicated between. Still referring to FIG. 28, the protruding portion 584 of the spring member 523 is dimensioned to engage an internal notch 590 formed in the housing 592 of the output spindle assembly 20. Lands 594 spaced from the rotation selector cam 520 along the circumference are formed between the notches 590. When the output spindle assembly 20 is disposed on the power transmission device assembly 16 and the speed selection mechanism 60 is disposed at one of the first, second and third rotational positions 500, 502 and 504. The protruding portion 584 of the spring member 523 engages one of the notches 590. The force generated by the spring member 523 when the protruding portion 584 moves downward in the direction of the rotation selector cam 520 in response to contact between the protruding portion 584 and the land 594 causes unintentional rotation of the speed selection mechanism 60. Acts to stop. Further, when the protruding portion 584 is disposed in the notch 590, the user is provided with a tactile indication of the position of the rotation selector cam 520.

  In the particular embodiment illustrated in FIGS. 13 and 27c, a switch portion 510 is shown that includes an arcuate band 600 having a protruding hollow rectangular selector button 602 formed therein. The arcuate band 600 is formed from a plastic material and has a shape that matches the outer diameter of the rotation selector cam 520. Since the open end of the selector button 602 is configured to receive the switch tab 532, the switch portion 510 and the rotation selector cam 520 are coupled together without a fastener. The plurality of spacing members 534 are protruding portions formed on the rotation selector cam 520, and extend outward in the radial direction coaxially with the selector main body 530. The spacing member 534 lifts the arcuate band 600 and prevents the arcuate band from contacting the wire tabs in the first cam slots 540a and 540b. The spacing member 534 may also be used to selectively reinforce a portion of the rotation selector cam 520, such as a range adjacent to the first cam slots 540a and 540b.

  As those skilled in the art will appreciate, the rotation selector cam 520 (i.e., the first cam slots 540a and 540b and the second cam slots 544a and 544b) are configured somewhat differently and the second ring gear 360 Meshes and engages both the second planetary gear 362 and the first reduction carrier 314, while the third ring gear 400 engages both the third planetary gear 402 and the third reduction carrier 404. In combination, the power transmission assembly 16 may be provided with a fourth overall gear reduction or speed ratio.

  As will be appreciated by those skilled in the art, a selection mechanism having another configuration may be substituted for the selection mechanism 60 illustrated in the present application. Such a selection mechanism may include an actuator that operates by rotational or sliding movement and is well known in the art for sliding the second and third ring gears 360 and 400 relative to the power transmission device sleeve 200. Interlocking devices, cams or other devices may be included. Also, as those skilled in the art will appreciate, the second and third ring gears 360 and 400 can move independently between the operating mode and the non-operating mode (ie, the second and third ring gears 360). 1 and 400 does not determine the other arrangement of the second and third ring gears 360 and 400), so that the switch mechanism 60 makes the second and third ring gears 360 and 400 independent of each other. You may comprise so that it may arrange.

Clutch Mechanism In FIGS. 23, 26, and 28 to 30, a clutch mechanism 18 including a clutch member 700, an engagement assembly 702 and an adjustment mechanism 704 is shown. The clutch member 700 is shown to be an annular structure fixed to the outer diameter of the first ring gear 310 and extending radially outward therefrom. The clutch member 700 includes an arcuate clutch surface 316 formed on the front surface 318 of the first ring gear 310. The outer diameter of the clutch member 700 is such that it rotates within a portion of the hollow cavity 212 formed by the base 216 of the power transmission device sleeve 200. With particular reference briefly to FIG. 29, the illustrated example clutch surface 316 is formed by a plurality of peaks 710 and valleys 712 that are arranged together to form a series of slopes formed by an angle of about 18 °. Will be shown. However, as those skilled in the art will appreciate, other clutch face shapes may be utilized, such as a sinusoidal clutch 316 ′ (FIG. 29a).

  Although the first ring gear 310 and the clutch member 700 are shown as a one-piece (ie, one-piece) structure, they may be different structures as those skilled in the art will recognize. One such embodiment is illustrated in FIG. 29 b, where the first ring gear 310 ′ is shown to include an annular collar 1000 and a plurality of tab openings 1002. The annular collar 1000 is illustrated to include a plurality of slopes 1004 that have double sloped sides but are otherwise flat. The first ring gear 310 ′ is otherwise identical to the first ring gear 310. The annular damper 1008 abuts the annular collar 1000 and engages the tab opening 1002 of the first ring gear 310 ′ to prevent the damper 1008 from rotating relative to the first ring gear 310 ′. 1010 included. The damper 1008 includes a body portion 1012 that is shaped to match the contour of the annular collar 1000 and thus includes a plurality of mating ramp portions 1014 that are shaped to engage each ramp 1004. The damper 1008 is formed from a suitable impact damping material such as acetyl. The clutch member 700 ′ is an annular member formed from a wear resistant material such as 8620 hardened steel and is disposed on the damper 1008. Similar to damper 1008, clutch member 700 ′ includes a plurality of tab members 1020 that are secured within tab opening 1002 to prevent rotation relative to first ring gear 310 ′, and a plurality of mating ramps 1022. However, the fitting inclined portion 1022 of the clutch member 700 ′ is fittingly engaged with the fitting inclined portion 1014 of the damper 1008. Such a structure is expensive compared to the previously described embodiments, but has a high tolerance for high impact forces associated with the operation of the clutch mechanism 18.

  In the particular embodiment illustrated, the engagement assembly 702 includes a pin member 720, a follower spring 722, and a follower 724. The pin member 720 includes a cylindrical body portion 730 having an outer diameter that is dimensioned to fit within a second portion 278 of an actuator opening 274 formed in the pin housing portion 248 of the power transmission sleeve 200. . The pin member 720 includes a tip portion 732 and a head portion 734. The tip portion 732 has a shape that engages with the adjustment mechanism 704. In the illustrated example, the tip portion 732 is formed at the end of the body portion 730 of the pin member 720 and is formed by a spherical radius. The head portion 734 is coupled to the end of the body portion 730 opposite the tip portion 732 and is in the form of a flat cylinder or barrel sized to fit within the first portion 276 of the actuator opening 274. That is, the head portion 734 prevents the pin member 720 from moving forward from the actuator opening 274.

  The follower spring 722 is a compression spring whose outer diameter is dimensioned to fit within the first portion 276 of the actuator opening 274. The front end of the follower spring 722 contacts the head portion 734 of the pin member 720, and the opposite end of the follower spring 722 contacts the follower 724. The end portion 740 of the follower 724 has a cylindrical shape and is dimensioned to fit within the inner diameter of the follower spring 722. In this regard, the follower end portion 740 serves as a spring follower that prevents the follower spring 722 from bending when compressed. The follower 724 also includes a follower portion 744 having a cylindrical body portion 746, a tip portion 748, and a flange portion 750. Body portion 746 is dimensioned to fit within first portion 276 of actuator opening 274. The tip portion 748 is shaped to engage the clutch surface 316 and is formed at the end of the body portion 746 of the follower 724 and is formed by a spherical radius in the illustrated example. Flange portion 750 is formed at the intersection between body portion 746 and end portion 740. The flange portion 750 is generally flat and is configured to receive a bias force due to the action of the follower spring 722.

  Also shown is an adjustment mechanism 704 that includes an adjustment structure 760 and a setting collar 762. The adjustment structure 760 is in the form of a generally hollow cylinder sized to fit in the housing portion 766 of the output spindle assembly 20. The adjustment structure 760 includes an annular surface 768 in which an adjustment profile 770 is formed. Adjustment profile 770 includes a leading adjustment section 772, a trailing adjustment section 774, a plurality of intermediate adjustment sections 776, and an inclined portion 778 between leading and trailing adjustment sections 772 and 774. In the illustrated embodiment, a second inclined portion 779 is included between the trailing intermediate adjustment section 776z and the trailing adjustment section 774. Also, in the particular embodiment illustrated, the portion of the adjustment profile 770 from the leading adjustment segment 772 to the last intermediate adjustment segment 776z is formed as a slope with a constant slope. That is, the follower 780 coupled to the housing portion 766 of the output spindle assembly 20 is biased radially outwardly toward the inner diameter of the adjustment structure 760 where the adjustment mechanism 704 (eg, setting collar 762). And abuts against a plurality of detents 782. The follower 724 and the plurality of detents 782 cooperate to provide the user of the tool 10 with a tactile indication of the position of the adjustment profile 770 and prevent the adjustment structure 760 from freely rotating to position the adjustment profile 770. One desirable adjustment section 772, 774 and 776 is maintained.

  The setting collar 762 is coupled to the outside of the adjustment structure 760 and includes a plurality of protruding grip surfaces 790 so that the user of the tool 10 can easily rotate both the setting collar 762 and the adjustment structure 760 to make the adjustment profile 770 desirable. One adjustment section 772, 774 and 776 can be set. A setting indicator 792 is utilized to display the position of the adjustment profile 770 relative to the housing portion 766 of the output spindle assembly 20. In the example provided, the setting indicator 792 includes an arrow 794 formed in the housing portion 766 of the output spindle assembly 20 and a scale 796 marked around the setting collar 762.

  As the tool 10 operates, the initial drive torque is transmitted from the motor assembly 14 to the first set of planetary gears 312 by the motor pinion 46, causing the first set of planetary gears 312 to rotate. In response to rotation of the first set of planetary gears 312, a first intermediate torque is applied to the first ring gear 310. The clutch torque applied by the clutch mechanism 18 resists this torque. The clutch torque prevents free rotation of the first ring gear 310 so that the first intermediate torque is applied to the first reduction carrier 314 and the rest of the reduction gear set 202, and the switch mechanism 60 is set. And multiplying the first intermediate torque by a predetermined method. In this regard, the clutch mechanism 18 biases the first reduction gear set 302 in the operating mode.

  The magnitude of the clutch torque is determined by the relative height of the adjustment mechanism 704, particularly the adjustment section 772, 774 or 776 that contacts the tip portion 732 of the pin member 720. When the adjustment mechanism 704 is disposed in one predetermined adjustment section 772, 774 or 776, the pin member 720 is pushed rearward within the actuator opening 274 and compresses the follower spring 722 to generate a clutch force. The clutch force is transmitted to the flange portion 750 of the follower 724, and the tip portion 748 of the follower 724 is engaged with the clutch surface 316 to generate the clutch force. When the tip portion 748 of the follower 724 is disposed in one of the valleys 712 of the clutch surface 316, the rotation of the first ring gear 310 relative to the power transmission sleeve 200 when the magnitude of the clutch torque exceeds the first intermediate torque is achieved. It will be a blocking action. However, when the first intermediate torque exceeds the clutch torque, the first ring gear 310 can rotate with respect to the power transmission sleeve 200. Depending on the shape of the clutch surface 316, rotation of the first ring gear 310 may increase the clutch force to a sufficient amount to prevent further rotation. In such a situation, the first ring gear 310 rotates in the opposite direction as the magnitude of the first intermediate torque decreases, aligning the tip portion 748 of the follower 724 with one of the valleys 712 of the clutch surface 316. If the rotation of the first ring gear 310 does not increase the clutch force sufficiently to fully resist the rotation of the first ring gear 310, the first reduction gear set 302 is placed in the inoperative mode and the first One ring gear 310 rotates to prevent transmission of the first intermediate torque to the first reduction carrier 314. In such a situation, the portion of the power transmission assembly 16 that is located in front of the first set of planetary gears 312 (eg, first reduction carrier 314, second sun gear 358, second set of planetary gears 362). ) No torque is transmitted.

  Configuring the clutch mechanism 18 in this manner resists the first intermediate torque rather than the output torque of the tool 10 where the clutch torque is generated by the multiple reduction power transmission assembly 16 and transmitted through the chuck 22. This is very advantageous in terms of size. In this regard, the clutch mechanism 18 can be relatively small in size and the ability to be incorporated or packaged into the tool 10 is improved. Moreover, because the speed or gear ratio is changed after the first ring gear 310, ie downstream thereof, the clutch mechanism 18 is operable over a relatively wide range of output torque. Compared to the conventional clutch mechanism that operates to limit the output torque of the power transmission device, such a device operates with a relatively narrow torque range, and it is necessary to replace the clutch spring when it is desired to greatly change the magnitude of the output torque. Become. In contrast, the clutch mechanism 18 of the present invention significantly changes the magnitude of the output torque of the tool 10 simply by operating the power transmission assembly 16 at different (ie, low or high) gear ratios. It can correspond to.

  When a rotary power tool such as the tool 10 is operated, it is desirable to switch between the two clutch settings, as in the case where the tool 10 is used to simultaneously drill a hole and then install a screw in the hole. There are many. Accordingly, the adjustment mechanism 704 rotates relative to the output spindle assembly 20 to place the adjustment mechanism 704 in one of the desired adjustment sections 772, 774 and 776 for a first operation, after which the second one The second operation may be performed by rotating to the adjustment sections 772, 774, and 776. Unlike known clutch mechanisms, the adjustment mechanism 704 of the present invention is configured such that the adjustment structure 760 and the setting collar 762 can rotate at an angle of 360 °. Assuming that the adjustment structure 760 is located in the intermediate adjustment section 776x, rotating the adjustment mechanism 704 at an angle of 360 ° means that the adjustment structure 760 along with the other intermediate adjustment sections 776 has a leading and trailing adjustment section 772. And 774 and the inclined portion 778, and the adjustment structure 760 is again placed in the intermediate adjustment section 776x. This feature is particularly advantageous when the clutch setting needs to be changed between a relatively high clutch setting and a relatively low clutch setting. In this regard, the sloped portion 778 causes the clutch collar 18 to move from the highest clutch setting corresponding to the last adjustment section to the lowest clutch setting corresponding to the first adjustment section. It is allowed to rotate without being set to one of the intermediate clutch settings. That is, the user of the tool 10 can change from the maximum setting to the minimum setting by rotating the setting collar 762a by a relatively small amount.

  Although the adjustment profile 770 has been described above as having a constant slope, as those skilled in the art will appreciate, the present invention may be configured somewhat differently in a broader manner. For example, the adjustment profile 770 ′ may be formed by adding detents (detents) as illustrated in FIG. 31 to each of the adjustment sections 772 ′, 774 ′, and 776 ′ of the head, tail, and middle. Good. In this arrangement, the adjustment sections 772 ′, 774 ′, and 776 ′ cooperate with the engagement assembly 702 to provide a tactile indication of the position of the adjustment profile 770 ′ to the user of the tool 10 and to free the adjustment structure 760. The detent 782 of the adjustment structure 760 and the follower 780 of the housing portion 766 of the output spindle assembly 20 are not necessary because it prevents rotation.

  Another example is illustrated in FIG. 32, where the adjustment profile 770 ″ is generally adjusted except that the sloped portion 779 is omitted and the trailing intermediate adjustment section 776z is immediately adjacent to the trailing adjustment section 774. Similar to the profile 770.

  While the invention has been described in the specification and illustrated in the drawings with reference to a preferred embodiment, it will be appreciated by those skilled in the art that various changes can be made without departing from the scope of the invention as defined in the claims. It is possible to make element changes and replace elements. In addition, many modifications may be made to the teachings of the invention to adapt to a particular situation or material without departing from the essential scope of the invention. Accordingly, the present invention is not intended to be limited to the specific embodiments illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the invention. Any embodiment within the scope of the appended claims is included.

1 is a side view of a power tool constructed according to the teachings of the present invention. FIG. FIG. 2 is an exploded perspective view of a part of the power tool of FIG. 1. FIG. 2 is a perspective view of a portion of the housing of the power tool of FIG. 1 illustrating the rear of the end cap assembly. It is a front view of an end cap assembly. FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. FIG. 2 is a rear view of a portion of the power tool of FIG. 1 with the end cap assembly removed. FIG. 2 is a side view of a portion of the power tool of FIG. 1 with the end cap removed. FIG. 5 is a view similar to FIG. 4 but illustrating the end cap shell before an overmold operation. FIG. 6 is a view similar to FIG. 5 but illustrating the end cap shell before an overmold operation. FIG. 5 is a view similar to FIG. 4 but illustrating an alternative structure of an overmold member. FIG. 11 is a partial cross-sectional view of a power tool utilizing an end cap assembly having an overmold member having a structure as illustrated in FIG. 10. FIG. 2 is an exploded perspective view of a portion of the power tool of FIG. 1 illustrating the power transmission assembly in more detail. FIG. 2 is an exploded perspective view of a portion of the power tool of FIG. 1 illustrating in more detail a reduction gear set assembly, a power transmission sleeve, a portion of a housing, and a portion of a clutch mechanism. FIG. 13a is a cross-sectional view along the longitudinal axis of the second ring gear. FIG. 13b is a cross-sectional view along the longitudinal axis of the third ring gear. It is a side view of a power transmission device sleeve. It is a rear view of a power transmission device sleeve. FIG. 16 is a cross-sectional view taken along line 16-16 of FIG. FIG. 17 is a cross-sectional view taken along line 17-17 of FIG. It is an exploded view of a reduction gear set assembly. 2 is a cross-sectional view along the longitudinal axis of the power tool of FIG. 1 illustrating a portion of the reduction gear set assembly in more detail. FIG. It is a front view of a part of the first deceleration carrier. 2 is a cross-sectional view along the longitudinal axis of the power tool of FIG. 1 illustrating a portion of the reduction gear set assembly in more detail. FIG. It is a rear view of a part of the third deceleration carrier. FIG. 2 is a cross-sectional view along the longitudinal axis of the power tool of FIG. 1 illustrating the power transmission assembly disposed at a first speed ratio. FIG. 24 is a cross-sectional view illustrating a power transmission assembly that is substantially similar to FIG. 23 but disposed at a second speed ratio. FIG. 24 is a cross-sectional view illustrating a power transmission device assembly substantially similar to FIG. 23 but arranged at a third speed ratio. FIG. 2 is a top view of a portion of the power tool of FIG. 1 illustrating a speed selection mechanism in further detail. FIG. 27a is a side view of the rotation selector cam. FIG. 27b is a top view of the rotation selector cam. FIG. 27c is a cross-sectional view through the central axis of the speed selection mechanism. It is a rear view of an output spindle assembly. It is a disassembled perspective view of a clutch mechanism. FIG. 29 a is a perspective view of a part of a clutch mechanism illustrating another configuration of the clutch member. FIG. 29B is an exploded perspective view illustrating the combined structure of the first ring gear and the clutch member. It is a schematic illustration of the adjustment structure in the state of “deployed on a plane”. FIG. 31 is a schematic illustration similar to FIG. 30 but showing an alternative structure for the adjustment profile. FIG. 31 is a schematic illustration similar to FIG. 30 but showing a portion of another alternative structure of the adjustment profile.

Claims (1)

A power tool,
A motor having an output shaft;
A power transmission device having a first portion having a first gear ratio and a second portion having an output gear ratio, wherein the first portion comprises a ring gear, a first sun gear, and a planetary gear. A planetary gear assembly with a gear assembly, wherein the ring gear is not shared with the second part of the power transmission device, and the planetary gear assembly comprises a single planet carrier and a plurality of planetary gears. The planetary carrier has a plurality of pins and a second sun gear that rotatably supports the plurality of planetary gears, and the plurality of planetary gears mesh with the first sun gear and the ring gear. The first sun gear is coupled to the output shaft and receives torque input from the motor, the second sun gear is in meshing engagement with the second portion and outputs an intermediate torque output; 2 is the intermediate torque output A power transmission device for generating a receive output torque,
A clutch assembly for limiting torque output of the power tool, wherein the clutch assembly includes an annular clutch member and an engagement assembly, the clutch member is coupled to the ring gear, and the clutch member is predetermined. And the engagement assembly has a follower member, and the follower member comes into contact with the clutch member only when the magnitude of the intermediate torque output is smaller than a predetermined maximum torque. A power tool comprising a clutch assembly that cooperates with a profile to prevent relative rotation between the clutch member and the follower member.

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